Cervical spinal nerve 6 originates from the spinal column through intervertebral foramen above cervical vertebra 6. According to Spine-Health, the C6 nerve controls the wrist extensor muscles that control wrist extension and hyperextension, which include the extensor carpi radialis longus, extensor carpi radialis brevis and extensor carpi ulnaris. The C6 also works in conjunction with the C5 nerve to innervate the biceps brachii.
The University of Kansas Medical Center notes that the C6 nerve innervates the suprapinatus, infraspinatus and teres minor muscles of the rotator cuff; the pectoralis major and serratus anterior muscles of the chest and ribs; the deltoid and brachialis of the upper arm, and the supinator, brachioradialis, pronator teres, extensor digitorum and extensor indicis of the forearm. The C6 also innervates the latissimus dorsi muscles of the back. The motor functions consistent with the C6 nerve include strong elbow flexion, shoulder rotation and adduction and abduction of the arm, according to the London Health Sciences Centre. Many of these muscle innervations are shared with the C5, C7, C8 and T1 nerves. Distally, the C6, C7, C8 and T1 nerve fibers form the median nerve. The median nerve passes through the carpal tunnel and supplies motor innervation to the muscles in the hand.
According to the London Health Sciences Centre, C6 also provides sensory function for the thumb side of the lower forearm, the thumb and the first finger.